Flame retardant fibrous material having improved dimensional stability

ABSTRACT

Fibrous material such as cotton cloth is simultaneously rendered flame retardant and imparted improved dimensional stability by treating the material with cyanamide and at least one phosphonic acid represented by the structural formula:   wherein R1 represents a divalent organic radical such as methylene or ethylene, X represents a covalent bond, -POOR3- or CO-; and R2 and R3 represent a monovalent radical such as hydrogen or methyl. Mixtures of these phosphonic acids with other phosphonic acids such as methyl phosphonic acid can give particularly advantageous results. Durability of the flame retardancy to repeated hard water washing may be improved through a subsequent treatment with additional cyanamide, with N-methylol compounds, or by methylation with diazomethane. Durable press properties of cellulosic textiles are also improved by the subsequent treatment with additional cyanamide. A particularly high degree of flame retardancy is imparted to mercerized cotton cloth.

United States Patent Swidler et al.

July 1, 1975 FLAME RETARDANT FIBROUS MATERIAL HAVING IMPROVEDDIMENSIONAL STABILITY Inventors: Ronald Swidler; William A.

Sanderson, both of Palo Alto; William A. Mueller, Pasadena, all ofCalif.

Cotton, Incorporated, New York, NY.

Filed: July 2, 1973 Appl. No.: 375,438

Related US. Application Data Continuation-impart of Ser. No. 259,350,June 2, 1972, abandoned, which is a continuation of Ser. No. 153,094,June 14, 1971, abandoned, which is a continuation of Ser. No. 862,509,Sept. 30, 1969, abandoned.

Assignee:

US. Cl 428/289; 106/15 FP; 252/8.1; 428/921; 427/333; 427/396 Int. ClC09k 3/28 Field of Search 117/136, 143 A, 139.4, 117/137; 106/15 FP;252/81; 260/502.4 R, 502.4 P, 928, 941, 953, 961

References Cited UNITED STATES PATENTS Primary ExaminerCharles E. VanHorn Assistant Examiner-Neal Kalishman Attorney, Agent, or Firm-Burns,Doane, Swecker & Mathis [5 7] ABSTRACT Fibrous material such as cottoncloth is simultaneously rendered flame retardant and imparted improveddimensional stability by treating the material with cyan amide and atleast one phosphonic acid represented by the structural formula:

wherein R represents a divalent organic radical such as methylene orethylene, X represents a covalent bond, POOR or CO; and R and Rrepresent a monovalent radical such as hydrogen or methyl. Mixtures ofthese phosphonic acids with other ph0sphonic acids such as methylphosphonic acid can give particularly advantageous results. Durabilityof the flame retardancy to repeated hard water washing may be improvedthrough a subsequent treatment with additional cyanamide, withN-methylol compounds, or by methylation with diazomethane. Durable pressproperties of cellulosic textiles are also improved by the subsequenttreatment with additional cyanamide. A particularly high degree of flameretardancy is imparted to mercerized cotton cloth.

21 Claims, N0 Drawings 1 FLAME RETARDANT FIBROUS MATERIAL HAVINGIMPROVED DIMENSIONAL STABILITY CROSS REFERENCE TO RELATED APPLICATIONSThis is a continuation in part of copending applica tion Ser. No.259,350, filed June 2, 1972, now abancloned, which in turn is acontinuation of application Ser. No. 153,094,filed June 14, 1971, nowabandoned, which in turn is a continuation of Ser. No. 862,509, filedSept. 30, 1969. now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to flame retardant fibercontaining material having improveddimensional stability and to processes for producing the same.

2. State of the Art Natural fiber-containing textile materials such ascotton cloth have been employed since ancient times. However, thecombustibility of these textile materials has inhibited their wider usein certain instances. A great number of flame retardants have beenproposed for use with cellulosic textile materials, but these flameretardants suffer from one or more disadvantages.

A major disadvantage of many prior flame retardants is their lack ofwash fastness or durability, by which is meant that while they initiallyrender the cellulosic textile material flame retardant, such flameretardancy disappears after one or more household launderings,especially in hard water. This phenomenon is described by OBrien inCyanamide-Based Durable Flame- Retardant Finish for Cotton, TextileResearch Journal, March 1968, pp. 256-266. This article describesimparting flame retardancy to cellulosic textile materials with flameretardants of cyanamide and phosphoric acid. However, the flameretardants disclosed therein by OBrien are not resistant to hard waterwashing. Similarly, East German Patents 15,357 and 18,253, and Schiffneret al. in Faserforsch u. TexilteclL, 14, (9), 375-86 (1963) describespecific attempts to impart flame resistance to textile material withcertain flame retardants, including combinations of urea ordicyandiamide with chloromethyl phosphonic acid, or urea withhydroxymethyl phosphonic acid, which combinations may also not beresistant or durable to repeated cycles of hard water washings, or whichmay unduly degrade the physical strengths of fabrics.

Also, many flame retardants are incompatible with crease-proofing agentscommonly employed for cellulosic materials; in the past this limitationhas discouraged use of flame retardants in conjunction with acrease-proofing operation so as to yield a cellulosic textile materialwhich is wrinkle resistant and dimensionally stable as well as flameretardant.

Other disadvantages include the relatively large quantities (highadd-on) which may be necessary in order to impart flame retardance andthe undesirable alteration of other properties of the cellulosic textilematerial such as color, hand and susceptibility to dye ing.

SUMMARY OF THE INVENTION Accordingly, a primary object of the presentinvention is to render fiber-containing material flame retardant andimpart improved dimensional stability while preventing or' substantiallyalleviating one or more of the above-discussed disadvantages of priorprocesses.

Another object is to provide an improved process for impartingdimensional stability and flame retardancy to cellulosic textilematerials which flame retardancy is durable and resistant to multiplehousehold launderings in general and especially in hard water.

Another object is to provide an improved cellulosic flame-retardingprocess requiring only a relatively small add-on or amount of flameretardants.

A still further object is to provide an improved process for renderingcellulosic textile material flame retardant which does not adverselyaffect the other prop erties of the material.

Another object of the present invention is to provide a cellulosicflame-retarding process having improved efficiencies'of reaction betweenthe flame retardants" and the cellulosic material.

Yet another object is to provide an improved process for renderingcellulosic textile material both flame retardant and wrinkle resistant,with improved dimensional stability.

Yet another object is to provide by these processes flame resistantfibrous products having improved dimensional stability.

Additional objects and advantages of the present invention will beapparent to those skilled in the art by reference to the followingsummary of the characteristic features of the present invention and thesubsequent description of the preferred embodiments:

In accordance with a primary aspect of the present invention, a processis provided for rendering or imparting flame retardancy and improveddimensional stability to cellulosic and wool fiber-containing materialcomprising contacting the material with cyanamide and at least onephosphonic acid represented by the structural formula:

II OH HOXRP 1| to deposit or fix on the material a flame-retarding anddimensional stability-improving amount of the phosphonic acid withcyanamide. In the above formula R represents a divalent organic radicalsuch as lower alkylene. lower alkylidene or lower alkylidyne; Xrepresents a covalent bond, POOR- or CO; and R and R represent the sameor different monovalent radical such as hydrogen or lower alkyl.

A central feature of the present invention is the discovery thatcyanamide and the above described phosphonic acids can impart durable,hard water washresistant, flame retardancy to cellulosic fibercontainingmaterial, particularly mercerized cotton cloth, while concurrentlyimproving dimensional stability. In addition, the fireretardancy-imparting systems of the present invention have improvedefficiencies in terms of efficiency of reaction between the flameretardants and the cellulose. and in terms of fire retardancy per unitadd-on of phosphorus.

In accordance with another aspect of the present invention, the fibrousmaterial rendered flame-retardant as indicated above is subsequentlytreated to improve the durability of flame retardancy to repeated hardwater washing by contacting the material with additional cyanamide.Also, this subsequent treatment with additional cyanamide has been foundto improve durable press properties of cellulosic textile material.

In accordance with yet another aspect of the present invention,durability of the flame retardancy of the fibrous material to repeatedhard water washing is improved by methylation of the acid form of thephosphonic acid residue on the fibrous material. In a preferredembodiment described below, such methylation is accomplished bycontacting the fibrous material with diazomethane.

In accordance with another aspect of the present invention. the fibrousmaterial rendered flame retardant by the phosphonic acid and cyanamideas indicated above is subsequently treated to improve the durability offlame retardancy to repeated hard water washing by contacting thematerial with at least one water-soluble compound possessing reactiveN-methylol groups, and thereafter curing the material to fix orinsolubilize the compound on the material.

Other aspects and advantages of the present invention will be apparentto one skilled in the art from the following:

DESCRIPTION OF THE PREFERRED EMBODIMENTS As indicated above, cyanamide(HNCNH or H NCN), also known as carbodiimide, is used along with certainphosphonic acids to impart the washresistant flame retardancy to thefibrous or fibercontaining material.

The phosphonic acids which may be suitable can be represented by thegeneral structural formula:

where R represents a divalent organic radical such as lower alkylene,lower alkylidene or lower alkylidyne; X represents a covalent bond,POOR" or CO; and R and R represent the same or different monovalentradicals such as hydrogen or lower alkyl. The alkyl radicals or portionsof the radicals may contain, for example, from I to 4 carbon atoms.

Non-limiting examples of phosphonic acids having the above-describedstructural formula and which may be used according to the process of thepresent invention include hydroxymethyl phosphonic acid, hydroxymethylphosphonic acid monomethyl ester, hydroxyethyl phosphonic acid,hydroxyethyl phosphonic acid mono t-butyl ester. methylene diphosphonicacid. ethylene diphosphonic acid, tetramethylene diphosphonic acid.carboxymethyl phosphonic acid, carboxyethyl phosphonic acid andcarboxyethyl phosphonic acid monomethyl ester. Mixtures of two or moreof the phosphonic acids may be used if desired.

Mixtures of at least one of the above phosphonic acids with othersubstituted phosphonic acids are also contemplated. Such othersubstituted phosphonic acids may include lower alkyl phosphonic acidssuch as methyl, ethyl. isopropyl and t-butyl phosphonic acids, loweralkoxyalkyl phosphonic acids such as methoxymethyl phosphonic acid.halo-substituted lower alkyl phosphonic acids such as chloromethyl andbromoethyl phosphonic acids, well as vinyl phosphonic acid, and monolower alkyl esters thereof such as ethyl phos- LIJ phonic acid monoethylester and methyl phosphonic acid monomethyl ester.

The more preferred single phosphonic acid systems are hydroxymethylphosphonic acid. hydroxyethyl phosphonic acid, ethylene diphosphonicacid and carboxymethyl phosphonic acid; and the more preferred mixedphosphonic acid systems are a mixture of at least one of the above withmethyl phosphonic acid, insofar as these particular systems have beenfound to give or impart the most durable flame retardancy to the fibrousmaterials, while concurrently improving dimensional stability.

The manner in which the phosphonic acids and cyanamide are prepared orderived is per se well known and does not form a part of the presejitinvention.

The cellulosic or wool fiber-containing material which may be treatedaccording to the present invention are generally any of those which havebeen previously employed in conjunction with known flame retardants. Thefiber-containing or textile material can have a wide variety of physicalforms and can be fibers, filaments, yarns, threads, and particularlywoven and nonwoven cloth. The cellulosic fiber material can be cotton,flax, linen, hemp, or regenerated cellulose such as rayon (e.g., viscoserayon). Mercerized cotton may give particularly advantageous results.(Mercerized cotton is well known per se; mercerization typicallycomprises passing cotton through, a 25 to 30 percent solution of sodiumhydroxide under tension, and then washing the cotton with waterwhileunder tension. Mercerization using liquid ammonia is also known.) Thesefiber-containing or textile materials can be mixtures of two or moredifferent fibers. e.g., a mixture of cellulosic fibers with otherfibrous materials such as nylon (e.g., nylon 6,6) polyester (e.g.,polyethylene terephthalate), acrylics (e.g., polyac'rylonitrile),polyolefins (e.g., polypropylene). polyvinyl chloride, polyvinylidenechloride, and polyvinyl alcohol fibers,

The preferred cellulosic textile materials are those containing 50weight percent or more of cotton and especially pure, i.e., essentiallylOO weight percent, cotton cloth.

According to a broad aspect of the present invention, fire or flameretardancy and improved dimensional stability can be imparted to fibrousmaterial by contacting or impregnating the material with the phosphonicacid and cyanamide under'widely varying conditions of temperature andpH. Yet. durable, i.e., wash resistant, flame retardancy and improveddimensional stability are imparted by fixing, i.e., reacting, thephosphonic acid with the cyanamide on the material. This fixing orcuring is generally accomplished by heating the treated material atsuperambient temperatures and at low pH. Broadly, any temperature can beemployed above which the phosphonic acid and cyanamide are fixed orreacted on the material and below which undesirable thermal degradationof the material begins, and generally from 20 to 400C and preferablyfrom to 300C. Optimum results are obtained at to 180C.

Durable flame retardance is imparted if, concurrently with the abovedescribed heating, the pH of the reacting mixture on the material islow. i.e., typically less than 2.5 and preferably less than 1.5, e.g.,about [.0 While these pHs are believed to be critical to durability itis generally valid to assume that the pH of the reacting mixture on thematerial is the same as the pH of the mixture of phosphonic acid,cyanamide, and solvent when present, except as indicted below for the insitu generation of the reactants.

The fibrous material may be contacted with a simple mixture of thephosphonic acid and cyanamide; and a solvent is preferably present. Thesolvent can be employed in any amount up to infinite dilution as long asthe final treated material has an add-on sufficient to impart flameretardancy and to improve dimensional stability, which add-on may be,for example, from 2 to weight percent. Add-on is defined and used hereinas the increase (dry" basis) in weight of the fibrous material due tothe addition of the flame retardant as a percentage of the weight of theuntreated fibrous material. Examples of suitable solvents include loweralkanols such as methanol and ethanol, lower alkylene or alkyl etherssuch as dioxane and ethyl ether, or, most preferably, water. Suchsolutions are termed pad baths.

The fibrous material can be contacted with the phosphonic acid andcyanamide sequentially but is preferably contacted with bothsimultaneously. This mixture of phosphonic acid and cyanamide can beemployed at autogenous pH which is generally about 0.8 or at a slightlyhigher pH, e.g., about 1.0 to 1.5, except as indicated below for the insitu generation of the reactants where the pH of the pad bath may varyup to 6.0. Naturally, in the latter case the pH of the pad bath may bequite different from the pH on the material at fixation.

A method by which the above described phosphonic acids can be formed insitu is by the thermal degradation of the corresponding ammonium saltsuch as monoor di-ammonium hydroxymethyl phosphonic acid, or ammoniumhydroxymethyl phosphonic acid monomethyl ester. For example, ammoniumhydroxide can be added to a pad bath containing the phosphonic acid(which would, of course, raise the pH, typically to about 3.0). Thus, inthe fixing step there is initially present, on the fibrous material,cyanamide and an ammonium salt of the phosphonic acid. Upon heating tofixation, the ammonium salt would decompose to ammonia and thecorresponding phosphonic acid (resulting in a lowered pH). Usage of suchammonium salts and the inherent raising of the pH of the pad bath can beadvantageous where lower pH (higher acidity) pads baths are not desireddue to corrosion and personnel handling considerations.

In a preferred process for rendering fibrous materials such ascellulosic textile materials flame retardant and improving dimensionalstability according to the present invention, the material is firstcontacted with an aqueous solution comprising a mixture of phosphonicacid and cyanamide at the desired pH in a molar ratio of 1:10 to 10:1,preferably 1:2 to 3:1, and most preferably 1:2 to 2:1. The excesssolution is then removed from the material by any suitable means such asby passing the material between the nip of two rollers. The material isthen dried to remove excess water. The drying can be accomplished at anytemperature but is generally accomplished at superambient temperaturesand preferably from to 150C. The material is then heated in order to fixthe phosphonic acid and cyanamide on the material and is conducted atthe above described fixation temperatures. The heating is conducted forat least several seconds and up to several hours, more typically fromone to 15 minutes. In certain instances, the fixing may be generallycomplete in within 2 to 10 minutes. The drying and heating steps can beconducted simultaneously but are preferably conducted sequentially. Thefixing of the phosphonic acid with the cyanamide on cellulosic materialis presently thought to occur in the form of a reaction product whichthen reacts with the hydroxyl groups of the cellulosic material.

The treated fibrous material preferably has sufficient add-on such thatit exhibits the desired degree of flame retardancy and improveddimensional stability. Such materials generally have add-ons of l to 30,and preferably l0 to 20 percent.

It is only critical to the present invention that the above describedphosphonic acids and cyanamide be present on the fibrous material.Therefore, according to another embodiment of the present invention manyof these compounds can be formed in situ. A preferred method by whichthe above described phosphonic acids can be formed in situ is by theabove-described thermal degradation of the corresponding ammonium saltsuch as ammonium hydroxymethyl phosphonic acid and monomethyl ester, ormonodi-ammonium hydroxymethyl phosphonic acid. Another method involvesthermally decomposable esters which upon heating yield theabove-described phosphonic acids can be employed. A third method may beby the use of metal salts of the phosphonic acids together with meansfor creating the low pHs necessary to effect fixation. For example, thepH of the pad bath may be increased with sodium hydroxide, followed bythe addition of ammonium chloride. Thus, in the fixing step there wouldbe present on the cellulosic material; cyanamide, a sodium salt of theabove described phosphonic acids, and ammonium chloride. Upon heating,the ammonium chloride would decompose to ammonia and hydrochloric acidconverting the sodium salt to the free acid to accomplish fixation.Naturally, in these cases the pH of the pad bath may be quite differentthan the pH on the material.

The solution of phosphonic acid and cyanamide into which the cellulosicmaterial is dipped may also contain, if desired, conventional softeners,lubricants, stiffeners, brighteners, water-repellants, soil releaseagents, and dyes.

The fibrous material rendered flame retardant as indicated above may besubsequently processed to improve durability of the flame retardancy bytreating the material with additional cyanamide, or diazomethane(methylation), or water-soluble compounds possessing reactive N-methylolgroups. When such further processing or retreatments" are employed, theacid form of the phosphonic acid residue typically needs to beregenerated such as by contacting or souring with a dilute hydrochloricacid solution. Such regeneration is typically necessary due to what isthought to be inherent chemical breakdown of cyanamide to produceeventually ammonia in the curing or fixation stage, which results in anammonium salt form of the phosphonic acid residue on the fabric. Andafter hard water washing, the phosphonic acid residues may inherently bepresent on the fabric as their calcium salts, as further explainedhereinbelow.

After laundering in hard water, the phosphonic acid residues are thoughtto be at least in part present on the fabric as their calcium salts,e.g.,

1 O Cellulose H- CP(O) And generally, for a given phosphonic acid theorder of flame retardant efficiency (char length) is acid monomethylester calcium salt. It is thought that cium pickup (increases resistanceto ion exchange) during hard water washings. As a consequence, flameretardance, and especially the durability of flame retardance, isimproved.

In the case of cellulosic textile materials, the further reaction of thephosphonic acid by the cyanamide is thought to be in the nature of acrosslinking reaction insofar as, surprisingly, dimensional stability orshrinkage control, durable press properties (wrinkle resistance), andoverall shape retention and wash/wear properties are also demonstrablyimproved.

When cyanamide is used in this subsequent treatment, the acid form ofthe phosphonic acid residue should be regenerated such as by contactingor souring with a dilute hydrochloric acid solution, and the souredfibrous material is then contacted or impregnated with cyanamide asgenerally indicated above for the initial flame retardancy treatment.For example, the material may be contacted with a solution of cyanamide.Examples of suitable solvents include methanol, ethanol, dioxane and,most preferably, water. The cyanamide is present in the solution or padbath in an amount sufficient to improve flame retardancy (or reduceionicity) as discussed above. For example, the concentration ofcyanamide in solution may range from about l to 50 weight percent, andmore typically, from to 20 weight percent. Higher or lowerconcentrations may be used if desired.

As in the initial treatment, any excess solution may then be removedfrom the fibrous material by any suitable means such as by passing thematerial between the nip of two rollers. The material may then be driedto remove excess water. The drying can be accomplished at anytemperature but is generally accomplished at ambient or superambienttemperatures, and preferably from 20 to 150C. The material with thecyanamide is then heated in order to further react the phosphonic acidresidue on the fibrous material. Broadly, any temperature can beemployed above which the phosphonic acid residue is further reacted withthe material by the cyanamide and below which undesirable thermaldegradation of the material begins, and generally from about 50 to 400C,preferably from 100 to 300C, and most preferably from 120 to 180C. Theheating is conducted for at least several seconds up to several hours,more typically from about 10 seconds to 2 hours and preferably fromabout 1 to minutes. The drying and heating steps can be conductedsimultaneously but are preferably conducted sequentially.

As indicated above, the treated material preferably has sufficientadd-on such that it exhibits the desired degree of flame retardancy.Such materials generally have add-ons of about 1 to 30, and preferablyabout 10 to percent.

When diazomethane is used in the subsequent treatment, the acid form ofthe phosphonic acid residue should be regenerated such as by contactingor souring with a dilute hydrochloric acid solution, and the souredfibrous material is contacted with diazomethane as generally indicatedabove for subsequent treatment with cyanamide. For example, the fibrousmaterial may be contacted, e.g., immersed, in an ether solution ofdiazomethane for about 1 to 2 hours at 0 to 30C. Such treatment withdiazomethane is thought to bring about methylation of the phosphonicacid residue, thus reducing ionicity and calcium pickup (increasingresistance to ion exchange), and improving flame retardancy, especiallydurable flame retardancy. Other methylating agents such as orthoesters,e.g., trimethyl orthoformate, may also be used to bring aboutmethylation of the phosphonic acid residue. These methylating agents arewell known per se and their production or derivation is not part of thepresent invention.

When one or more N-methylol compounds are used in the subsequenttreatment, the acid form of the phosphonic acid residue should beregenerated such as by contacting or souring with a dilute hydrochloricacid solution, and the soured fibrous material is contacted with theN-methylol compound and is thereafter cured to fix or insolubilize thecompound on the material.

The water-soluble compounds possessing reactive N- methylol groups,sometimes referred to herein as N- methylol compounds, include thesubstantially water soluble precondensates which are obtained bycondensation of formaldehyde with a compound such as melamine, or alower alkyl-substituted melamine, or a urea. The resultingmethylol-containing compound or precondensate may be further etherifiedby reaction with a lower alkanol such as methanol or butanol. As is wellknown in the fabric treating art, these precondensates are capable ofbeing applied to fibrous materials from an aqueous solution. Goodresults may be obtained, for example, using precondensates obtained bycondensing 1 mole of melamine or an alkyl substituted melamine with l to6 moles of formaldehyde, i.e., using mono-, di-, tri-, tetra-, penta-,or hexa-methylol melamine. Such products function well to increase flameretardance durability and can be readily fixed or cured on fibrousmaterial by heating as described herein. Commercially available productsof this kind include Aerotex 23, an alkylated melamine-formaldehydeprecondensate, Aerotex M-3, a dimethoxymethyl hydroxymethyl melamine;Aerotex P-225, a hexakis (methoxymethyl)melamine; Aerotex 19, which is aless completely fractionated modification of Aerotex P-225, and Aerotex92 which is a melamine having an average of about 1.5 methylol groups.These Aerotex products are supplied by American Cyanamide Company.Equivalent products are commercially available from other manufacturerssuch as Monsanto Company which produces Resloom HP, which is a melaminehaving an average of about 2 to 3 methylol groups. To be applied bypadding, one or more of the aforementioned N-methylol compounds may bedissolved in water to form a soluble containing from about 1 to 50%,preferably about 5 to 20%, N-methylol compound. To facilitateinsolubilization or formation of polymer on the fabric in a desiredamount, it may be desirable in certain cases to add to the paddingsolution, a catalyst such as formic acid, citric acid, hydrochloricacid, or, particularly, an acid-acting salt such as zinc nitrate, zincchloride, magnesium chloride, ammonium chloride, aluminum chloride,sodium hydrogen phosphate,

methylol compound in the fiber is typically aided by heat in addition toacidity. After application of the N- methylol compound to the fibrousmaterial, the latter is dried and finally cured under conditionsessentially the same as or similar to those described earlier herein inconnection with the subsequent treatment with cyan- 1O amide.

Application of the N-methylol compound-containing solution to thefibrous material may be done by conventional padding using customaryequipment, or by other processes well known in the art. Typically, thesoducted at ambient temperature, e.g., between about 10 and 30C. As inthe initial treatment, any excess solution may then be removed from thefibrous material by any suitable means such as by passing the materialbetween the nip of two rollers. The material may then be dried to removeexcess water. The drying can be accomplished at any temperature but isgenerally accomplished at ambient or superambient temperatures, andtypically from 20 to 100C. The material with the N- methylol compound isthen heated in order to fix or insolubilize the N-methylol compound onthe fibrous material. Broadly, any temperature can be employed abovewhich the N-methylol compound is reacted on the material and below whichundesirable thermal degradation of the material begins, and preferablyfrom 100 to 300C, and most preferably from 120 to 180C. The heating isconducted for at least several seconds up to several hours, moretypically from about 10 seconds to 2 hours and preferably from about 1to 15 minutes. The drying and heating steps can be conductedsimultaneously but are preferably conducted sequentially.

Such treatment with N-methylo1 compounds has been found to reduceionicity and calcium pickup (increasing resistance to ion exchange),thus improving durable flame retardancy. Increased durability of flameretardancy through such subsequent treatment with N- methylol compoundswas unexpected insofar as the utilization of such compound in theinitial pad baths containing the phosphonic acid and cyanamide reducedflame retardancy. Moreover, other conventional creaseproofing agentssuch as dimethylol dihydroxy ethylene urea have been found not toincrease significantly the durability fo flame retardancy.

If desired, more than one subsequent treatment with 55 additionalcyanamide or diazomethane or N-methylol compound may be used.Combinations of subsequent treatments with diazomethane and N-methylolcompound and retreatments with cyanamide may also be The presentinvention is further illustrated by the following examples; all partsand percentages in the examples as well as in other parts of thespecification and claims are by weight unless otherwise indicated. Thesenon-limiting examples are illustrative of certain embodiments designedto teach those skilled in the art how to practice the invention and torepresent the best mode contemplated for carrying out the invention.

EXAMPLE I This example illustrates the illustrates the process of thepresent invention employing cyanamide and hydroxyethyl phosphonic acid(HEPA) or HEPA-methyl phosphonic acid (MPA) acid mixture (runs 1 and 2,respectively) in aqueous solutions as shown in TABLE I. Comparison run 3was also made using cyanamide and methyl phosphonic acid (MFA) inaqueous solutions as shown in TABLE 1.

For each run, a weighed piece of cotton twill measuring 12 X 12 incheswas dipped into the aqueous solution or pad bath of cyanamide andphosphonic acid and then passed between the nip of two rollers to removethe excess solution. The cloth was then dried in an oven for 10 minutesat C and the cured (fixed) in a second oven for 15 minutes at 160C. Thefabric was then washed once as described below, dried, conditioned at65% relative humidity at 21C and reweighed. The difference between theinitial weight of the sample prior to the contact with the solution andfinal weight of the cloth after one wash divided by the initial weightof the cloth times is recorded in TABLE 1 as add on. This procedure wasrepeated for each of the remaining solutions.

Each of the samples was then washed the indicated number of times in anautomatic home laundering machine having one wash and two rinses withintermediate spin dry operations. A hard water solution of householdlaundry detergent, commercially available as ALL Laundry Detergent, wasemployed in the rinses. In this example, the term hard water refers toIrvine, Calif, water containing a degree of hardness equivalent to350-380 ppm of calcium carbonate. Total dissolved solids amount to750-850 ppm. The flame retardancy was then measured according toAmerican Association of Textile Chemists and Colorists (AATCC) procedure34-1966 and the char length in inches is shown in TABLE I. (The greaterthe char length, the less the flame retardancy.) A qualitative pass(+)/fail vertical strip-match test was also given to each of the treatedsamples. Dimensional stability was determined by measuring percentshrinkage in the warp direction.

As may be seen from TABLE I, the HEPAzcyanamide system (run 1 imparted aflame retardance durable for at least 40 washes, and vastly improveddimensional stability at 50 washes as compared to the MFA:- cyanamidesystem (run 3) or the untreated control. The mixed acid system,l-lEPA-MPA: cyanamide (run 2), imparted a flame retardance durable forat least 50 washes, and improved dimensional control to a degree similarto that obtained in run 1 with HEPA.

TABLE I THE EFFECT OF PHOSPHONlC AClD/CYANAMIDE SYSTEMS ON FLAMERETARDANCE AND DlMENSlONAL STABILITY TABLE I -Continued CyanamideAcidzCyanamide Add-On P N Run No. Acid Used in Bath (71) Ratio (7() (71)(7:)

Flame Retardance=Char Length (in.) and Match Test Warp Shrinkage (72) atNumber at Number of Washes Shown (ALL Detergent) of Washes Shown Run No.1 10 20 40 50 1 10 60 1 2 /2 3 /2 3 7 BEL 5 6 2 1% 2 i) 1% i) 2 (i) 2% 46.25 3 1 (+1 2 "-1 2 2 2% 5 17 Untreated Control 9.6

The bath also contained. in addition to the cyanamide and phosphonicacid. 0.1 percent Triton X-IOO non-ionic wetting agent and 5 percentVelvnmine 380 polyethylene softener.

(4-) passed match test; failed match test: (:1 burned greater than 3inches but not entire length.

EXAMPLE 11 This example illustrates certain embodiments of the presentinvention employing cyanamide with hydroxymethyl phosphonic acid (HMPA)alone (run 4) and admixed with certain other phosphonic acids (runs 5 to8) or orthophosphoric acid (run 9) and gives a comparison to the use ofcyanamide with such other phosphonic acids alone (runs 10 to 13) orvinyl phosphonic acid (VPA) alone (run 14).

The procedure of Example I was repeated employing the same quantities ofthe same ingredients and the same times, procedures and conditionsexcept with the various systems shown in TABLE II which includes dataand test results for the runs.

As may be seen from TABLE 11, runs 4 to 9 utilizing systems of thepresent invention imparted flame retardance and improved dimensionalstability to the cotton fabric.

EXAMPLE 111 This example illustrates the process of the presentinvention employing cyanamide and carboxymethyl phosphonic acid (runs 15and 16) or carboxyethyl phosphonic acid (runs 17 and 18) in solutions ofvarying acid: cyanamide ratio. The procedure of Example 1 was repeatedemploying the same quantities of the same ingredients and the sametimes, procedures and conditions except with the various systems shownin TABLE III which includes data and test results for the runs; and withthe exception that, instead of Irvine water, Menlo Park, Calif., waterhaving a hardness equivalent equal to 32 ppm calcium carbonate was usedin the wash and rinse cycles.

As may be seen from TABLE 111, runs 15 to 18 utilizing systems of thepresent invention imparted flame retardance and improved dimensionalstability to the cotton fabric.

TABLE II THE EFFECT OF PHOSPHONIC ACID/CYANAMIDE SYSTEMS ON FLAMERETARDANCE AND DIMENSIONAL STABILITY Flame Retardance =Char Length (in.)

Run Add-On P N and Match Test at Number of Washes Warp Shrinka e (7()No. Acid Mixture 7t (71) (7:) 1 10 20 1 10 50 4 HMPA 18.9 3.04 0.53 30-)BEL 5 5 5 MFA-HMPA 15.6 2.88 0.73 2(t) 2%() 2%() 3%() 3%() 5 7.5 6EPA-HMPA 15.4 2.61 0.71 2(i) BEL 5 6.25 7 CMPA-HMPA 16.7 2.74 0.93 2()2() BEL 5 5.5 8 MMPA-HMPA 16.7 2.60 0.75 2Vz(-) 2%(-) BEL 5 5 1"EDPA-HMPA 18.4 3.09 0.76 BEL 5 5 9 H;,PO ,-HMPA 20.3 2/2(-) BEL 4 5 10MFA 17.7 3.28 0.61 1%(1'1 2() 2( 2(-) 2'/4(-) 5 10 17 11 EPA 16.3 2.710.49 2'/2(-) 4%() 5 15 12 CMPA" 2.61 1.34 29H) 13.3 13 MMPA 16.1 2 370.67 3%() 3%() BEL 15 14 VPA 17.7 2%(-) 3V2() BEL Flame returdanceresults shown are not believed to be reliably indicative of the elficacyof the system tested. 2:125 ratiu used. Estimate. "EPA is ethylphosphonic acid: CMPA is chloromethyl phosphonic acid; MMPA ismethoxymcthyl phosphonic acid; l-IDPA is ethylene diphusphonic acid.

TABLE 111 EFFECT OF CARBOXY PHOSPHONIC ACIDS/CYANAMlDE SYSTEMS ON FLAMERETARDANCE AND DlMENSlONAL STABlLlTY NOTE C, AC) 2 HOOC CH PO(OH) C ACIDHOOCCH CH PO(OH) Flame Retardance Shrinkage 7: Acid 71 '71P %N /(P 71NOne Fifty Washes Run Concentration AcidzCyanamide Add- One One FiftyFifty One Fifty Hundred No. Acid in Bath Ratio On 71 Wash Wash WashesWashes Wash Washes Washes Warp Fill 15 C 25 1:2 19.0 2.40 1.04 2.20 1.132(+) 3() 3() 7.0 0.5 16 C, 25 1:3 19.6 2.46 2.04 2 36 1 64 2(+) 2(+)2(+) 6.0 0.5 17 C 25 1:2 16.0 1.80 0.05 2 /2() BEL 15.0 2 18 C 25 11315.4 1.93 0.86 6() BEL 10.0 1.0 Untreated 9.6 1.0

TwillControl EXAMPLE IV This example illustrates certain preferredembodiments of the present invention employing cyanamide with a mixtureof hydroxyethyl phosphonic acid weight percent Velvamine 380polyethylene softener. The fabric samples are then dried in an oven for10 minutes at 80C and then cured in a second oven for IS minutes at160C. Each of the fabric samples is washed (HEPA) and methyl phogphonicacid (MPA) and gives the indicated number of times in an automatic homeacomparison to the effect of mercerization of the cotlalmclermg i havmgone ,wash and two rmses ton (flannel) fabric with intermediate spin dryoperations. A hard water so- The procedure of Exumplel run 7 ig repeatedlution of household laundry detergent. commercially ploying the samequantities of the same ingredients and avallable Laundry g j,emlyfloyefl m the same times, procedures and conditions with the extheIn l example I e hdrd i ception that unmercerized flannel cloth (BariumN0 fers to lrv1ne,Calif., water containing a degree of hard- 100) wasused for run 19 and mercerized flannel Cloth ness equivalent to 3 50480ppm of calcium carbonate. (Barium 154) was used in run Also Memo Totaldissolved solids amount to 750850 ppm. The Park water having a hardnessequivalent of 24 ppm Calflame retardancy is then measured according toAmeri- Cium Carbonate was used instead of the Irvine waten canAssociation of Textile Chemists and Colorists The results are recordedin TABLE Iv. (AATCC) procedure 34-1966. Durable press proper- AS may beSeen from TABLE IV, the flame retard ties are measured according toAATCC 88A-I964T. ancy for the mercerized flannel (Run 20) was durablelonlcity is measured y I'mg the fabric with dilute for at least 0 Washeshydrochloric acid, rinsing the fabric with distilled water Mercerizationof Cotton is believed to increase the 20 and then titrating with sodiumhydroxide solution. Ti number of anhydroglucose units available forreaction, anon effected by l l the tubnc l "6556] g he removes them fromrelatively impenetrable crys distilled water and monitoring byconventional potentitalline regions of the cellulose. Thus, when a givenOmelet t hnique. H amount of flame retardancy imparting reactants is 5Durable flame retardance, dimensional stability and plied to thecellulose, the concentration of reactive durable press prOPemes are allImproved by retreat sites on a mercerized fabric is greater relative toa simimam wlth Cyanamlde' lar but unmercerized fabric, and hence, theefficiency EX M V of immobilization is increased (i.e., wash-off is de-A PLE l creased). This phenomena is significant insofar as effi- Thisexample illustrates certain preferred embodiciencies of reactants,durability of flame retardancy, ments of the present invention employingcyanamide and overall process economies are improved. and hydroxyethylphosphonic acid with one or more TABLE IV EFFECT OF MERCERIZATION RunMerccrized or 7( Acid HEPAzMPA: /r /1N /(P Flame Rctardancc No. AcidFabric Unmercerized in Bath Cyanamide Ratio Add-On One Wash One WashAfter Fifty Washes l9 HE- Flannel Unmcrcerized 21 l:l:4 l2.7 0.47 2.56BEL PA/MPA 1:1 20 HE- Flannel Mercerized 21 l:l:4 22.1 0.66 3.47 */z()PA/MPA lzl EXAMPLE V diazomethane (CH N retreatments to improve dura-This example illustrates certain preferred embodi ments of the presentinvention employing cyanamide and hydroxyethyl phosphonic acid (HEPA)with one or more retreatments with additional cyanamide.

Five pieces of cotton twill are dipped into an aqueous solutioncontaining 25 weight percent hydroxyethyl phosphonic acid, 16 weightpercent cyanamide, 0.1 weight percent Triton X-lOO non-ionic wettingagent and 5 weight percent Velvamine 380 polyethylene softener. Thefabric samples are then dried in an oven for 10 minutes at 80C and thencured in a second oven for 15 minutes at 160C. The fabric samples arethen washed, dried and conditioned as described in Example I. One fabricsample is used as a control, while the remaining four fabric samples aresubjected to from 1 to 4 retreatment operations with additionalcyanamide to improve durable fire retardancy (reduce ionicity) and toimprove also the durable press properties of the fabric. Eachretreatment operation includes souring the fabric sample with a dilutehydrochloric acid solution and dipping the fabric sample into an aqueoussolution containing 16 weight percent cyanamide, 0.1 weight percentTriton X-l00 non-ionic wetting agent and 5 EXAMPLES Vll-Vlll Theseexamples illustrate certain preferred embodiments of the presentinvention employing cyanamide with hydroxyethyl phosphonic acid on wooland on rayon fabrics.

The procedure of Example I (run l is repeated employing the samequantities of the same ingredients and the same times, procedures andconditions with the exception that the cotton twill was replaced bybleached, undyed wool in one run, by dyed wool (grey) in another run andby rayon twill in a third run. Durable 15 16 flame retardance andimproved dimensional stability described in Example 1, except that MenloPark, Calif., are observed for each of the treated fabrics. water havinga hardness equivalent equal to 40 ppm calcium carbonate was used insteadof the Irvine, EXAMPLE 1X Calif, water. One fabric sample was used as acontrol,

5 while the remaining three fabric samples were sub- Example 1 (run 2)repelited employmg the j jected to further processing with N-methylolcomquantities of the same ingredients and the same times, pound toimprove durable fire retardancy (reduce iom rocedures and conditionswith the exce tion that the l i drox eth l hos honic acid is replaces byethylene may) The subsequent Procebsmg mcluijed spurmg hog l the bathContainin fabric samples with a dilute hydrochloric acid solution E ,l hmeth l hog ghonic l0 and dipping the fabric samples into an aqueoussolution et ene 1p 08p Omc dc] y p containing 0.1 weight percentEthoquad 18/5 non-ionic acid and 19% cyanamide. Flame retardance and im-1 t proved dimentional stability for the treated fabric are wettmgdgempoldsm ABS polyethylene Softener and various amounts of Resloom HPmethylolated melobberved' amine in varying amounts as shown in TABLE X1.The EXAMPLE X fabric samples were then dried in an oven for 5 minutes at65C and then cured in a second oven for 5 minutes This exampleillustrates the present invention when at 140C. Each of the fabricsamples was then washed cyanamide. methyl phosphon c acid andhydroxyethyl the indicated number of times in an automatic homephosphonic acid are applied to a fabric from a pad bath launderingmachine having one wash and two rinses which also contains ammoniumhydroxide to increase with intermediate spin operations. A householdlaunthe otherwise autogenous pH of the path to a pH of 3. dry detergent,commercially available as ALL laundry The procedure of Example 1V (run20) was repeated detergent, was employed in the washes. Flameretardemploying the same quantities of the same ingredients ancy andionicity were measured as in Example V. As and the same times,procedures and conditions with the may be seen from TABLE X1, durableflame retardexception that the pH ofthe pad bath in the run was ad ancewas achieved, with reduced ionicity.

TABLE XI Flame Rctardancy of HMPAzMPAzCyanamide Systems with SubsequentTreatment of N-methylol Compound Run No. N-mcthylol Compound FlameRetardancc Analysis (One lonicity (One in Bath (9 One Wash (in.) FiftyWashes (in.) Wash) /1N Wash)meq./gm

1 none (control) 1% 2 1.17 2 2.5 1% 1 5.22 0.82 3 5 1% 1% 5.00 0.69 47.5 1% 1*/4(+) 6.50 0.57

justed to a pH of 3 with ammonium hydroxide. and the The principles.preferred embodiments and modes of fabric sample was dried at about 65Cfor 8 minutes 40 operation of the present invention have been describedand cured at about 160C for 5 minutes, and reactant in the foregoingspecification. The invention which is ratios were as shown in TABLE X.The resulting flame intended to be protected herein, however, is not tobe retardancy values are also shown in TABLE X. construed as limited tothe particular forms disclosed, As may be seen from TABLE X, good flameretardsince these are to be regarded as illustrative rather then ancywas achieved. restrictive. Variations and changes may be made by TABLE XAcid Acid Ratio Acid:Cyanamide /2P /ll l Flame Retardancc Ratio Onc Wash(in.) Fifty Washes (in.)

MPA- 4:1 1:2 2.90 0.59 1% 2 HEPA EXAMPLE X1 those skilled in the artwithout departing from the spirit of the present invention.

This example illustrates certain preferred embodiments of the presentinvention employing cyanamide. hydroxymethyl, phosphonic acid, andmethyl phosphonic acid with subsequent treatments with N- methylolcompound to improve the durability of the flame retardancy.

Four pieces of mercerized cotton flannel were dipped into an aqueoussolution containing 13.5% methyl phosphonic acid, 5.2% hydroxymethylphosphonic acid, and 16% cyanamide. The fabric samples were then driedin an oven for 8 minutes at C and then 0 cured in a second oven for 5minutes at C. The fab- HOXRlg OH ric samples were then washed, dried andconditioned as OR We claim: 1. A process for imparting flame retardanceand im- 60 proved dimensional stability to cellulosic and woolfibercontaining material, which process comprises contacting thematerial with cyanamide and at least one phosphonic acid represented bythe structural formula:

wherein R represents a divalent radical selected from the groupconsisting of lower alkylene, lower alkylidene and lower alkylidyne; Xrepresents a co valent bond,

or CO, and wherein R and R represent monovalent radicals selected fromthe group consisting of hydrogen and lower alkyl; to deposit on thematerial a flame retarding and dimensional stabilityimproving amount ofthe phosphonic acid with cyanamide.

2. A process according to claim 1 wherein the material is cellulosic andis contacted with hydroxyethyl phosphonic acid, ethylene diphosphonicacid, carboxymethyl phosphonic acid. or a mixture of at least onethereof with methyl phosphonic acid.

3. A process according to claim 1 for imparting flame retardance andimproved dimensional stability to cellulosic fiber-containing material,which process comprises contacting and fixing on the material withcyanamide a flame-retarding and dimensional stabilityimproving amount ofat least one phosphonic acid represented by the structural formula:

wherein R represents a divalent radical selected from the groupconsisting of methylene and ethylene; X represents a covalent bond orand wherein R represents a monovalent radical selected from the groupconsisting of hydrogen and methyl; and wherein during contacting themolar ratio of phosphonic acid to cyanamide is from 1:10 to :1.

4. A process according to claim 3 wherein the material is fixed byheating the material for a period of time and at a temperature at leastsufficient to give an addon of from 1 to wherein the phosphonic acid andcyanamide are in solution when contacted with the material; wherein thepH at fixation is less than 2.5; and wherein the cellulosicfiber-containing material is cotton cloth.

5. A process according to claim 3 wherein the cellulosicfiber-containing material is fixed by contacting the material with thephosphonic acid and cyanamide and then heating the material at atemperature between about 100 and 300C.

6. A process for imparting flame retardance and improved dimensionalstability to cellulosic textile mate rial comprising in sequence thesteps of:

l. contacting the material with an aqueous solution of cyanamide and atleast one phosphonic acid selected from the group consisting of ethylenediphosphonic acid, carboxymethyl phosphonic acid and hydroxyethylphosphonic acid, wherein the molar ratio of phosphonic acidzcyanamide is1:10 to 10:1 and Il. heating the material to fix at a pH less then 2.5the phosphonic acid with cyanamide on the material to give an add-on ofbetween about 1% and 30% 7. A process according to claim 6 for impartingdura- 5 ble flame retardance and improved dimensional stability tocellulosic fiber-containing textile material. which process comprises insequence the steps of:

l. contacting the material with an aqueous mixture of cyanamide with thephosphonic acid wherein the molar ratio of phosphonic acidzcyanamide is1:10 to 10:1, and;

11. fixing the retardancy in the material at a pH less than 1.5 byheating the material until a dimensional stability-improving add-on ofbetween about 1 and 30% is achieved and the flame retardancy becomesdurable to at least 30 hard water washes.

8. A process according to claim 7 wherein the cellulosic material ismercerized cotton cloth and the aqueous solution further includes methylphosphonic acid. and the flame retardancy is durable to at least 50 hardwater washes.

9. A process according to claim 7 wherein the aqueous mixture ofcyanamide and phosphonic acid further contains ammonium hydroxide. andan ammonium salt of the phosphonic acid is deposited on the textilematerial.

10. A process for imparting durable flame retardance and improveddimensional stability to cellulosic and wool fiber-containing material.which process comprises the steps of:

l. contacting the material with cyanamide and at least one phosphonicacid represented by the structural formula:

wherein R represents a divalent radical selected from the groupconsisting of lower alkylene, lower alkylidene and lower alkylidyne; Xrepresents a covalent bond.

or CO, and wherein R and R represent monovalent radicals selected fromthe group consisting of hydrogen and lower alkyl; to deposit on thematerial a flame retarding and dimensional stability' improving amountof the phosphonic acid with cyanamide; and subsequently ll. contactingthe material with at least one member selected from the group consistingof cyanamide. diazomethane and water-soluble compounds possessingreactive N-methylol groups. in an amount sufficient to improve thedurability of the flame retardancy of the material to repeated hardwater washing.

11. A process according to claim 10 wherein in step (1) the phosphonicacid and the cyanamide are in solution when contacted with the materialand the molar ratio of phosphonic acid to cyanamide is from 1:10 to10:1; and in step (11) the cyanamide is in solution when contacted withthe material, and the material is thereaf ter heated to give a totaladd-on of from 1 to 30%.

12. A process for rendering cellulosic textile material durably flameretardant, dimensionally stable and wrinkle resistant, which processcomprises the steps of:

l. contacting the material with an aqueous mixture of cyanamide and atleast one phosphonic acid selected from the group consisting of ethylenediphosphonic acid. carboxymethyl phosphonic acid and hydroxyethylphosphonic acid, wherein the molar ratio of phosphonic acidzcyanamide is1:10 to 10:1, and

11. heating the material to fix at a pH less than 2.5 the phosphonicacid with cyanamide on the material to give an addon of between about 1%and and Ill. contacting the material with an aqueous solution ofcyanamide and heating the material to improve the durability ofthe flameretardancy, dimensional stability, and durable press properties of thematerial.

13. A process according to claim 12 for rendering cottonfiber-containing textile material durably flame retardant and forsimultaneously improving the dimensional stability and durable pressproperties of the textile material, which process comprises in sequencethe steps of:

l. contacting the material with an aqueous solution of cyanamide withthe phosphonic acid wherein the molar ratio of phosphonic acidzcyanamideis 1:10 to 10:1,

11. fixing the retardancy in the material at a pH less than 1.5 byheating the material until an add-on of between about 1 and 30% isachieved and the flame retardancy becomes durable to at least 30 hardwater washes; and

111. regenerating an acid form of fixed phosphonic acid residue on thematerial and then contacting the material with an aqueous solution ofcyanamide and heating the material to improve the durability of theflame retardancy to at least 50 hard water washes, and to improvedimensional stability, and durable press properties of the material.

14. A process for rendering cellulosic textile material durably flameretardant, dimensionally stable and wrinkle resistant, which processcomprises the steps of:

I. contacting the material with an aqueous solution of cyanamide and atleast one phosphonic acid selected from the group consisting of ethylenediphosphonic acid, carboxymethyl phosphonic acid and hydroxyethylphosphonic acid, wherein the molar ratio of the phosphonicacidzcyanamide is 1:10 to 10:1, and

II. heating the material to fix the phosphonic acid at 20 a pH less than2.5 with cyanamide on the material to give an add-on of between about 1%and 30%, and

Ill. contacting the material with an aqueous solution of at least onewater-soluble compound possessing reactive N-methylol groups and curingthe material to improve the durability of the flame retardancy of thematerial.

15. A process according to claim 14 for rendering cottonfiber-containing textile material durably flame retardant and forsimultaneously improving the dimensional stability and durable pressproperties of the textile material. which process comprises in sequencethe steps of:

l. contacting the material with an aqueous mixture of cyanamide with thephosphonic acid wherein the molar ratio of phosphonic acidzcyanamide is1:10 to 10:1,

11. fixing the retardancy in the material at a pH less than 1.5 byheating the material until an add-on of between about 1 and 30% isachieved and the flame retardancy becomes durable to at least 30 hardwater washes; and

ill regenerating an acid form of fixed phosphonic acid residue on thematerial and then contacting the material with an aqueous solution ofthe N- methylol compound, and heating the material to cure and thedurability of the flame retardancy is improved to at least hard waterwashes.

16. A process according to claim 15 wherein the textile material ismercerized cotton cloth, and wherein the aqueous mixture of cyanamideand phosphonic acid further contains ammonium hydroxide, and an ammoniumsalt of the phosphonic acid is deposited on the textile material.

17. A flame retardant material produced according to the process ofclaim 1.

18. A durably flame retardant material having improved dimensionalstability produced according to the process of claim 7.

19. A durably flame retardant material having improved dimensionalstability produced according to the process of claim 10.

20. A durably flame retardant and wrinkle resistant material producedaccording to the process of claim 13.

21. A durably flame retardant material having improved dimensionalstability produced according to the process of claim 15.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,892,906

Dated JuJ Y l, 1975 Inventor(s) Ronaldidler et a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

IN THE CLAIMS Column 18, line 45, delete the formula and insert [SEAL]Attest:

RUTH C. MASON Arresting Officer Signed and Scaled this C. MARSHALL DANNCommissioner of Patents and Trademarks UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent NO- 3 892 906 Dated Juli] l 1975 RonaldSwidler et al.

Inventor(s) It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

IN THE CLAIMS Column 18, line 45, delete the formula and insert Signedand Sealed this fourteenth Day Of October 1975 [SEAL] Arrest:

RUTH c. MASON c. MARSHALL DANN Arresting Officer Commissioner ufParentsand Trademarks

1. A PROCESS FR IMPARTING FLAME RETARDANCE AND IMPROVED DIMENSIONALSTABILITY TO CELLULOSIC AND WOOL FIBER-CONTAINING MATERIAL, WHICHPROCESS COMPRISES CONTACTING THE MATERIAL WITH CYANAMIDE AND AT LEASTONE PHOSPHONIC ACID REPRESENTED BY THE STRUCTURAL FORMULA:HO-X-R1-P(=O)(-OH)-O-R2 WHEREIN R1 REPRESENTS A DIVALENT RADICALSELECTED FROM THE GRUP CONSISTING OF LOWER ALKYLENE, LOWER ALKYLIDENEAND LOWER ALKYLIDYNE, X REPRESENTS A COVALENT BOND, -P(=O)-O-R3OR -CO-,AND WHEREIN R2 AND R3 REPRESENT MONOVALENT RADICALS SELECTED FROM THEGROUP CONSISTING OF HYDROGEN AND LOWER ALKYL, TO DEPOSIT ON THE MATERIALA FLAME RETARDING AND DIMENSIONAL STABILITY-IMPRVING AMOUNT OF THEPHOSPHONIC ACID WITH CYANAMIDE.
 2. A process according to claim 1wherein the material is cellulosic and is contacted with hydroxyethylphosphonic acid, ethylene diphosphonic acid, carboxymethyl phosphonicacid, or a mixture of at least one thereof with methyl phosphonic acid.3. A process according to claim 1 for imparting flame retardance andimproved dimensional stability to cellulosic fiber-containing material,which process comprises contacting and fixing on the material withcyanamide a flame-retarding and dimensional stability-improving amountof at least one phosphonic acid represented by the structural formula:4. A process according to claim 3 wherein the material is fixed byheating the material for a period of time and at a temperature at leastsufficient to give an add-on of from 1 to 30%; wherein the phosphonicacid and cyanamide are in solution when contacted with the material;wherein the pH at fixation is less than 2.5; and wherein the cellulosicfiber-containing material is cotton cloth.
 5. A process according toclaim 3 wherein the cellulosic fiber-containing material is fixed bycontacting the material with the phosphonic acid and cyanamide and thenheating the material at a temperature between about 100* and 300*C.
 6. Aprocess for imparting flame retardance and improved dimensionalstability to cellulosic textile material comprising in sequence thesteps of: I. contacting the material with an aqueous solution ofcyanamide and at least one phosphonic acid selected from the groupconsisting of ethylene diphosphonic acid, carboxymethyl phosphonic acidand hydroxyethyl phosphonic acid, wherein the molar ratio of phosphonicacid:cyanamide is 1:10 to 10:1 and II. heating the material to fix at apH less then 2.5 the phosphonic acid with cyanamide on the material togive an add-on of between about 1% and 30%.
 7. A process according toclaim 6 for imparting durable flame retardance and improved dimensionalstability to cellulosic fiber-containing textile material, which processcomprises in sequence the steps of: I. contacting the material with anaqueous mixture of cyanamide with the phosphonic acid wherein the molarratio of phosphonic acid:cyanamide is 1:10 to 10:1, and; II. fixing theretardancy in the material at a pH less than 1.5 by heating the materialuntil a dimensional stability-improving add-on of between about 1 and30% is achieved and the flame retardancy becomes durable to at least 30hard water washes.
 8. A process according to claim 7 wherein thecellulosic material is mercerized cotton cloth and the aqueous solutionfurther includes methyl phosphonic acid, and the flame retardancy isdurable to at least 50 hard water washes.
 9. A process according toclaim 7 wherein the aqueous mixture of cyanamide and phosphonic acidfurther contains ammonium hydroxide, and an ammonium salt of thephosphonic acid is deposited on the textile material.
 10. A process forimparting durable flame retardance and improved dimensional stability tocellulosic and wool fiber-containing material, which process comprisesthe steps of: I. contacting the material with cyanamide and at least onephosphonic acid represented by the structural formula:
 11. A processaccording to claim 10 wherein in step (I) the phosphonic acid and thecyanamide are in solution when contacted with the material and the molarratio of phosphonic acid to cyanamide is from 1:10 to 10:1; and in step(II) the cyanamide is in solution when contacted with the material, andthe material is thereafter heated to give a total add-on of from 1 to30%.
 12. A process for rendering cellulosic textile material durablyflame retardant, dimeNsionally stable and wrinkle resistant, whichprocess comprises the steps of: I. contacting the material with anaqueous mixture of cyanamide and at least one phosphonic acid selectedfrom the group consisting of ethylene diphosphonic acid, carboxymethylphosphonic acid and hydroxyethyl phosphonic acid, wherein the molarratio of phosphonic acid:cyanamide is 1:10 to 10:1, and II. heating thematerial to fix at a pH less than 2.5 the phosphonic acid with cyanamideon the material to give an add-on of between about 1% and 30%, and III.contacting the material with an aqueous solution of cyanamide andheating the material to improve the durability of the flame retardancy,dimensional stability, and durable press properties of the material. 13.A process according to claim 12 for rendering cotton fiber-containingtextile material durably flame retardant and for simultaneouslyimproving the dimensional stability and durable press properties of thetextile material, which process comprises in sequence the steps of: I.contacting the material with an aqueous solution of cyanamide with thephosphonic acid wherein the molar ratio of phosphonic acid:cyanamide is1:10 to 10:1, II. fixing the retardancy in the material at a pH lessthan 1.5 by heating the material until an add-on of between about 1 and30% is achieved and the flame retardancy becomes durable to at least 30hard water washes; and III. regenerating an acid form of fixedphosphonic acid residue on the material and then contacting the materialwith an aqueous solution of cyanamide and heating the material toimprove the durability of the flame retardancy to at least 50 hard waterwashes, and to improve dimensional stability, and durable pressproperties of the material.
 14. A process for rendering cellulosictextile material durably flame retardant, dimensionally stable andwrinkle resistant, which process comprises the steps of: I. contactingthe material with an aqueous solution of cyanamide and at least onephosphonic acid selected from the group consisting of ethylenediphosphonic acid, carboxymethyl phosphonic acid and hydroxyethylphosphonic acid, wherein the molar ratio of the phosphonicacid:cyanamide is 1:10 to 10:1, and II. heating the material to fix thephosphonic acid at a pH less than 2.5 with cyanamide on the material togive an add-on of between about 1% and 30%, and III. contacting thematerial with an aqueous solution of at least one water-soluble compoundpossessing reactive N-methylol groups and curing the material to improvethe durability of the flame retardancy of the material.
 15. A processaccording to claim 14 for rendering cotton fiber-containing textilematerial durably flame retardant and for simultaneously improving thedimensional stability and durable press properties of the textilematerial, which process comprises in sequence the steps of: I.contacting the material with an aqueous mixture of cyanamide with thephosphonic acid wherein the molar ratio of phosphonic acid:cyanamide is1:10 to 10:1, II. fixing the retardancy in the material at a pH lessthan 1.5 by heating the material until an add-on of between about 1 and30% is achieved and the flame retardancy becomes durable to at least 30hard water washes; and III. regenerating an acid form of fixedphosphonic acid residue on the material and then contacting the materialwith an aqueous solution of the N-methylol compound, and heating thematerial to cure and the durability of the flame retardancy is improvedto at least 50 hard water washes.
 16. A process according to claim 15wherein the textile material is mercerized cotton cloth, and wherein theaqueous mixture of cyanamide and phosphonic acid further containsammonium hydroxide, and an ammonium salt of the phosphonic acid isdeposited on the textile material.
 17. A flame retardant materialproduced according to the process of claim
 1. 18. A durably flameretardant material having improved dimensional stability producedaccording to the process of claim
 7. 19. A durably flame retardantmaterial having improved dimensional stability produced according to theprocess of claim
 10. 20. A durably flame retardant and wrinkle resistantmaterial produced according to the process of claim
 13. 21. A durablyflame retardant material having improved dimensional stability producedaccording to the process of claim 15.